Deep-oxide planar buried-channel AlGaAs–GaAs quantum well heterostructure waveguides with low bend loss

Abstract

Data are presented on planar S-bend waveguides fabricated in an AlxGa1−xAs–GaAs p-n quantum well heterostructure (QWH) crystal by a self-aligned process combining Si impurity-induced layer disordering and ‘‘wet’’ native oxidation. In the process, a deep, low-index (n∼1.7) oxide cladding structure is formed, creating a buried channel in the QWH core layers and defining the routing properties of ∼2.5-μm-wide guides. Deep-oxide S-bend waveguides with 100 μm offsets exhibit low excess bend losses with a 3 dB transition distance less than 140 μm for transverse electric polarization. These bend losses are significantly lower than those measured for oxide-only and disordered-only guides. Excellent optical isolation of the guided signal is observed, indicating very little crosstalk occurs between adjacent guides.